1. Field of the Invention
The present invention relates to a liquid container which is attachably and detachably installed on an ink jet recording apparatus and contains a liquid such as ink for recording.
2. Description of the Related Art
As one form of a recording unit for use in an ink jet recording apparatus, there is one type which has a configuration such that a liquid container is detachably attached to a recording head mounted on a scanning carriage. In this type of liquid container, it is necessary to generate a prescribed negative pressure with respect to the recording head. In this regard, there is another type which utilizes an ink retaining force of a negative pressure producing member which is housed in the ink container and impregnated with ink. This type of liquid container is provided with a liquid supply port through which the contained liquid (ink) is supplied to the recording head, and an atmospheric air communicating port for communicating an interior of the liquid container with atmospheric air and allowing atmospheric air to be introduced into the liquid container.
In the above-described liquid container, if ink seeps from the negative pressure producing member due to a drastic change in the environment at the time of physical distribution, ink may, in some cases, eventually leak from the atmospheric air communicating port to the outside of the liquid container.
As a measure to prevent the ink leakage from the atmospheric air communicating port caused due to a change in the environment and the like, a liquid container which employs a configuration as described in Japanese Patent Application Laid-Open No. 08-090783, for example, has been proposed. In the liquid container disclosed in Japanese Patent Application Laid-Open No. 08-090783, a space (a buffer space) 209 is provided between a negative pressure producing member 204 in the liquid container 201 and an atmospheric air communicating port 203 provided on an upper wall of the liquid container 201 in a state in which the liquid container 201 is used, as shown in FIG. 7. By trapping ink leaking from the negative pressure producing member 204 into the space 209 so as not to allow the leaking ink to reach the atmospheric air communicating port 203, the ink leakage from the inside of the liquid container 202 to the outside can be suppressed.
In addition, a liquid container as disclosed in Japanese Patent Application Laid-Open No. 09-272210 has been proposed as shown in FIG. 8A and FIG. 8B. In this type of liquid container, as shown in FIG. 8A, two atmospheric air communicating paths 211 are configured by forming two grooves on an outer surface of the upper wall in the state in which the liquid container 201 is used and by covering the grooves with a seal tape 212. Further, as shown in FIG. 8B, an ink trap region 210 is provided as an independent space in one part of the liquid container 201. One end of one atmospheric air communicating path 211 is joined to an atmospheric air communicating port 203 which passes through the upper wall of the liquid container 201, and the other end of the one atmospheric air communicating path 211 is joined to the ink trap region 210. One end of the other atmospheric air communicating path 211 is open to atmospheric air by being exposed out of the seal tape 212, and the other end of the other atmospheric air communicating path 211 is joined to the ink trap region 210. With the configuration described above, a space 209 in an upper portion of the liquid container 210 is communicated with atmospheric air via the atmospheric air communicating port 203, one atmospheric air communicating path 211, the ink trap region 210, and the other atmospheric air communicating path 211.
The liquid container 201 shown in FIG. 8A and FIG. 8B is provided with the independent ink trap region 210 in addition to the space 209 provided between the atmospheric air communicating port 203 and the negative pressure producing member 204 employed by the liquid container 201 shown in FIG. 7. Because the liquid container 201 is provided with the ink trap region 210, it is possible to trap ink into the ink trap region 210 even if the ink moves towards the outside of the liquid container 201 through the atmospheric air communicating port 203. Accordingly, it is possible to prevent ink from leaking to the outside of the liquid container 201.
In this regard, the configuration of the above-described liquid container is effective in a case where the level of an impact applied to the liquid container at the time of physical distribution is low. In addition, the configuration of the above-described liquid container is also very effective for preventing ink leakage in a case where the attitude of the liquid container at the time of use thereof is fixed to a prescribed one as in the case of use in a desktop type recording apparatus.
Meanwhile, a mobile type recording apparatus which can be carried to any place by a user, for example, is attracting attention. A liquid container mounted on such a mobile type recording apparatus is carried and used under various kinds of impact, attitude, or environment, as opposed to a desktop type recording apparatus. As for the liquid container used in the recording apparatus which is subjected to the above situation, the countermeasures for the ink leakage as shown in FIG. 7, FIG. 8A, and FIG. 8B are not sufficient because ink may leak from the liquid container.
More specifically, as for the liquid container shown in FIG. 7, FIG. 8A, and FIG. 8B, the mobile type recording apparatus is supposed to be handled in such a manner that the atmospheric air communicating port 203 faces downward in a state in which ink is trapped in the space 209 or the ink trap region 210. If the mobile type recording apparatus is carried in such a manner that various kinds of impacts are applied or various kinds of change in the environment occur in the above situation, the trapped ink may sometimes leak from the liquid container.
One example of a state in which ink leaks from the liquid container is described with reference to FIG. 9A and FIG. 9B. FIG. 9A and FIG. 9B illustrate cross sections of a conventional type liquid container 201 and are views showing the state in which an atmospheric air communicating port 203 faces downward.
For example, as shown in FIG. 9A, suppose a state in which ink is moved due to the impact of falling or the like in such a manner as to penetrate into an ink nonimpregnated region 205 in a negative pressure producing member 204, and closed air bubbles 207 are formed in an ink impregnated region 206. In this case, if the ambient pressure is reduced as in the case of transportation on an airplane or the like, the closed air bubbles 207 are expanded as shown in FIG. 9B. When the closed air bubbles 207 are expanded, ink in the negative pressure producing member 204 is pushed out of the negative pressure producing member 204, and eventually, ink seeps from the negative pressure producing member 204. The seeped ink then accumulates in a buffer space 209 formed with ribs 208 between the negative pressure producing member 204 and a surface having the atmospheric air communicating port 203 formed thereon of the liquid container 201. Since the accumulated ink is directly communicated with the atmospheric air communicating port 203, the ink may easily leak to the outside.